Electrical testing device



Jan- 8, 1952 M. PODELL 2,581,497

ELECTRICAL TESTING DEVICE Filed Jan. 23, 1948 2 SHEETS-SHEET l IN V EN TOR.

BY /l/drnk far/fl] Jan- 8, 1952 M. Pom-:LL 2,581,497

ELECTRICAL TEsTNG DEVICE Filed Jan. 25, 1948V 2 SHEETS-SHEET 2 INVENTOR.

Patented Jan. 8, 1952 FELCE.

2,581,497 `ELEcrRIoAi. TESTING DEVICE Morris Podell, New York, N. Y. `Applimimn January 23, 194s, serial No. 3,953

The .present invention relates `generally to `an indicating device or a testing device which may `be used for testing electrical circuits or apparatus andmore particularly to a portable pocket type .of electrical testing device adapted to be utilized lfor conducting such tests as are generally re- .'ferred toas continuity tests and line or circuit tests.

For some time there has existed a need for an inexpensive 'and compact testing device that couldbe utilized for making electrical tests and ywhich wouldgive reliable, visible indications as to thecondition or" the piece of equipment or cir- `lize testlampsof the relatively rugged and inexpensive Vgaseous tube electric-discharge type for giving anindication of whether current is or is not owing through a line or piece of equipment, but the use of such lamps is widely objected to by electricians, radio'repair'men and the likefor the reason that use of such lamps is extremely deceptive. Lamps-of this type,'of which-neon is a well known example, 'are Vvery sensitive `and hence `they light in response to very minute currents. Frequently a neon lamp utilized in a testing' device will light or illuminate even during the testing of `a fuse which is actually blown out, due to `the factthat a circuit is completedthrough the electricians bodyand the ground, instead of through the fuse. A similar situation may occur in instances where a motor coil orother pieceof apparatus is beingtested. A particular example of deceptive neon indications on present devices occurs when live wires are 'adjacent to dead wires in the sameconduit, and the dead wires are tested.` Ignition of the test lamp under such circumstances Aleads an i electrician to believe that the particular part of 4 Claims. (Cl. 175-2183) embodying neon indicating lamps. As a result ,of theioregoing drawbacks it has been necessary pensive and possesses a shorter life.

The present invention `aims to overcome or .minimize the above and other diiculties or disadvantages by providing a new and improved `electrical indicating or testing device. The new and improved testing device `may embody a gaseous tube electric dischargelamp, or neon `lamp, `.which does not, with the new device, give false indications when usedin the testing of electrical circuits, appliances or pieces of equipment. 'The invention further contemplates the provision of a new ,andimproved device which mayibe utilized for conducting several of various typeso'f electrical tests.

An lobject of the present invention is to provide a new and improved testing device.

Another object of the invention is to provide a new and improved electrical indicating or testing deviceincorporating visible indicator means.

Another object ofthe invention is to provide a newand improved electrical testing device which is adaptedto give accurate'indications.

Another Aobject ofthe present invention is to provide 4an electricaltesting device'which may be utilized for conductingvarious` types 'of electrical tests.

Still another object ofthe-invention i-s-toprovide a newand improved electrical testing device utilizing a visible indicator of `-thefgaseous `tube electric discharge type.

Other and furtherrobject-sof the invention will be obvious upon an understanding of the illustrative embodiment about to be described, orn will be indicated in the appended claims, andvarious ladvantages"nct'referred Vto `herein will cccur'to one skilled inthe 'art upon `employment of 'the invention Ain practice.

A preferred embodiment ofthe inventionhas been chosen for purposes ofillustration and .description and `is shown in the accompanying drawings, forming .apart ,of the speoication, wherein:

Fig. l is a perspective view showing one form of the present invention;

lfig. 2.isaJ sectional .viewtaken along the line 2-,2 of Fig. 1;

Fig. 3 is a sectionalview takenralongthe `line 3--3 of Fig. 2

Fig. 4yisasectionalview taken along the line .4-4 of Fig. ,3;

Fig. 5 is a diagrammatic view showing one form of electrical hook-up for the device illustrated in Figs. l through 4;

Fig. 6 is a perspective view showing another form of the invention; 5

Fig. 7 is a sectional view showing a detail of the device illustrated in Fig. 6

Fig. 8 is a view showing the device of the present invention being utilized for conducting a continuity test;

Figs. 9a, 9b, and 9cillustrate, in a general way, the present device used for conducting continuity tests with various appliances or -pieces of equipment including some of inductive or capacity characteristics;

Fgs. 10a. and 10b illustrate the present device utilized to conduct circuit or line tests;

Fig. 11 is a diagrammatic view showing another form of electrical hook-up which may be used with the devicesof Figs. 1 through 10; and

Fig. 12 is a diagrammatic view showing a further form of electrical hook-up which may be used.

Referring more particularly to Figs. 1 through 5, there is shown one form of the present electrical testing device. As shown in these figures the device comprises a plurality of conductors I and 2, adjacent one end of each of AWhich is secured an attachment plug II having prongs or terminals 'l and 8 projecting therefrom; the prongs 'I and 8 are adapted to make contact with leads of a suitable current supply line. The conductors or wires I and 2 may be of any suitable length.

A portion of the conductors will generally eX- tend around the body portion IIJ of the device (Fig. l) and through one or more openings 9 (Fig. l) of the body portion I0. The opposite ends of the conductors or wires I and 2 are shown extending into handle portions II and I2, each of the handle portions being provided with a conducting test prong or pin I3 and I4. The testing prongs may be assembled with end caps I5 and I6 and the latter may be fitted rmly into the ends of the handle portions II and I2. The handles I I and I2 preferably have a tubular form, Which is convenient to hold, and are comprised of some suitable insulating material so that a user may grasp the handles and conduct various tests with minimum possibility of accidentally receiving electrical shocks.

One of the handle portions is shown provided with a Window or opening I1 in a wall thereof through which an interiorly disposed gaseous tube electric discharge lamp 22 may be vievved. The interior construction of the handles is shown diagrammatically in Fig. 5 of the drawings.

In Fig. 5 one of the wires or conductors I is shown connected with a resistance I9', of suitable value, and the resistance is connected at its op- 60 posite end with a test prong I3. The other wire or conductor 2 connects with a test prong I4 through a suitable resistance 20 and a lamp 22 of the gaseous tube electric discharge type. At neon lamp will generally be used as they are 65 readily available and are comparatively inexpensive to purchase; the lamp is preferably of such size as to fit closely within the tubular handle portion I2 adjacent the cut outs or openings I1 so that one looking into the opening I'I 70 may readily determine Whether or not the lamp 22 is illuminated or giving off a glow.

Y It will be noted in Fig. 5 that the lamp is shown coupled or connected in parallel with a capacitance or condenser 23, the latter being like- 7 Wise located within a handle portion I2 and coupled around both the resistance 20 and lamp 22. It has been discovered that coupling the condenser or capacitance in parallel with the gaseous tube lamp 28 brings about an entirely unusual result by providing a neon lamp testing device which gives accurate indications of the electrical condition of a circuit or piece of apparatus being tested. This very important feature will be further discussed hereinafter.

The wires or conductors I and 2 may be prevented from normally pulling away from the handle portions II and I2 in any suitable manner, for example, by providing them with suitable clamps or by forming a knotted portion 3 within the handle portion adjacent an end cap through which the wires extend.

When not being used for test purposes the test handle portions II and I2 may be retained in recesses formed or provided at opposite sides of the body portion I0 of the device (Figs. l through 5). An eilcient and satisfactory body portion may be provided by forming opposite halves I8 l and 2l from some synthetic molding material,

the separately formed halves being maintained together by one or more grommets or the like 24. By forming the separate halves to provide complementary retaining recesses adjacent their outer edges, the outer edges thereof may normally remain spaced apart by a sufficient amount to allow springing the parts to allow for moving the test handle portions II and I2 in and out between them. The natural resilience of the material comprising the body portion I0 is such as to effectively retain the test handle portions II and I2 assembled with the body portion I0, yet the test handle portions may be readily removed by pulling them outwardly with respect to the body portion.

Preferably the over all length of the handle portions and test prongs is such that when they are assembled or snapped between the retaining recesses, the ends of the test prongs are contained within the resulting housing. In this Way the prongs are not likely to accidentally injure a user who is carrying the device in his pocket.

One end of the body portion It] is shown widened or formed to provide a recess 26 and a U-shaped strip of conducting material is fitted into and retained by the opposite halves of the body portion IB. The opposite halves may fric; tionally grip the conducting strip or may be formed with a retaining ledge 21 to more positively retain the U-shaped conducting strip assembled `with the body portion I. When the prongs I and 8 of an attachment plug 4 are tted into the recess 26 between spaced leg portions of the conducting member 25, the test device may be utilized, for making line or circuit tests as herein described. Also, with the attachment plug in this position and the holding members II and I2 retained by the side edge portions of the body I0 the device may be conveniently carried in a pocket.

The test device shown in Fig. 6 is generally similar to that of Figs. 1 through 5 and comprises a plurality of conductors Ia and 2a to which is secured an attachment plug 4a, the plug having terminals la. and 8a for making contact with a source of current supply. rIhe conductors are shown coiled together and may be of any suitable length, with separate wires Ia and 2a passing through openings 28 and 29 of a. non-conducting block-like member 3!) so as to retain the block member with the wires at all times. The block aparaat'.

portions` HaV and |2at similar to the `form de,l

scribed inFigs. lthrough 5-1` and likewise isproe vided. with: test prongs` |30. and I4a, and cutoutszorropenings .Ha for viewing a gaseous tube lamp locatedzwithin the handle portion |2a. The form of.` the testing device illustrated in Fig. 6 preferably includes the same electrical hook up asfisindicated diagrammatically in Fig. 5. -Wheni the testing device of Figs. 1 through 6 is utilized for testing a piece of equipment such as--iai iiuorescent lamp, fuse, motor coil, or the likelFigs. 8, 9a, 913,` 9c), the attachment plug 4 or cfmay beinsertedinto a suitable wall receptacle Mein-Vorder toA supplyl current to the test prongs -andL Mor I3a and"` Ma. When the test prongs areiappliedf across the piece of equipment being tested, in the manner indicated generally in Figs. 8-` and# 9,- theneon lamp will light or glow, providing t-here is a continuous path through the piece ofi equipment being tested. That is, if thereisa continuous path or a continuity condition existing the lamp will glow and indicate the satisfactory or unsatisfactory condition as the case maybe, of the'particular piece of equipment being tested. In the event the piece of equipment is defective. the lamp will so indicate andthe electricianimmediately knows the source of trouble; In conducting tests such as are shown inFigs; 8 and 9 the device of Figs. l through 6 used as a continuity tester. In Fig. 8 the particular form ofdevice shown in Figs. lthrough 5" is utilized for` conducting the test but this is merely illustrative as the form shown in Fig. 6 may be vusedin similar manner.

` The resistanceunits shown in Fig. 5 adjacent the test prongsA i3 and I4 are desirablesince they `limit current through the line and, by thus minimizing the possibility of excessive current passing throughrthe testing device or the particular piece of equipment being tested, they insure against damaging the equipment. This is particularly desirable in instances where a delicate piece of equipment is being tested as it provides a protective feature which prevents the possibility` ofpassing excessive current which might burn out the device. The resistances prevent thefpassage of excessive currents upon the test prong being placed into contact with the apparl'atus being tested; Excellent results have been obtained' in actual conditions, by utilizing re.- sfstances lrand 2U each having values of ap pfoximateiy 100,000 ohms.

AAs pointed out hereinabove, it has been .discovered that when a 'suitablecapacitance or condenser 23 is coupled in parallel with a gaseous tube electric discharge lamp 22 the lamp` gives highlylsatisiactory and unexpected results in that false indications, seemingly due to body capacitance or the like, are eliminated or minimized. A capacitance or condenser of any suitable size may be utilized. It has been discovered that a capacitance or condenser having a value of from approximately .025 microfarad to about .035 microfarad has proven satisfactory for testing appliances or devices utilizing voltages of approximately 100 volts to 600 volts; a condenser with a capacity of approximately .03 microfarad is preferably used since it gives excellent results in this voltage range with cycle alternating current. A condenser of this approximate capacity is thus adapted to facilitate the conducting of various kinds of; tests of a relatively wide range of voltages. There is thus provideda widely use z.V4

ful testing device which gives accurate visi'ble'inf` dications of the conditionof a particular pieceuoi' equipment being tested.

Alamp 22 of the neon variety having a rating of 1/25 watt gives good results, but other;

suitable types and ratings of lamps may be used4 In Figs;` 10a and 10b the present device is shown as utilized for the conducting of what are referred to as linel or circuittests. That is, the device is being utilized to determine whether the particular line or circuit is` alive When utilized' in this manner the prongs l andi of the attach-l0 ment plug 4 are fitted into therecess 26 ofthe test appliance illustrated in Figs. 1-5, or into the spacedapertures 3l and 32 of the block-like member B forming part of the test applianceillustrated more particularly in Fig. 6. When the test prongs l and 8 or la and Sa are thus inserted they 'are placed into contact with a contact bar or member 25 or 34. As shown in Fig. 3thecon` tact member is of substantially U-shape with the legs being normally urged inwardly to readily l makeVV contact with theprongs 'i and 8 of an attachment plug 4.

With a closed circuit thus formed across the rather than in parallel with both a lampand a.

resistance. The hook-up of Fig. 5 is preferred` however since it nasbeen found to give enhanced results in actual operation.

Fig.` 12 illustrates a modified form of the inv vention wherein an additional resistance 3l is connected across the conductors Ib and 2b.. This` feature is useful in that it eliminates the necessity of removing the` attachment plug 4b from a..

receptacle or socket and reversing .and reinserting it therein toinsure that the correct polarity.

is .effective with a piecefof equipmentbeing tested,

in a particular type of testing. The inclusion of;

the .resistance 31 in the present` test deviceproe` videsl for correct indications by al test lampY re.- gardless of how the test prongs 'ib and 8b are-in: sertedintdthe receiving openings of receptacle with respect to the polarity of conductors connected Withreceptacle contacts or terminals..

While the test device feature of the gaseous.

tube electric discharge lamp coupled in parallel Withafcapacitance has been described more par` ticul'arl'y with reference to its use with the form of. test device shown Figs. 1 and', vit will be clear that this highly advantageous feature mai7 be embodied in test devices of modified forms; it may, for example, be used with one leg of multipurpose test pliers used by electricians and radio repair men.

It will be seen that the present invention provides a new and improved electrical testing device which may be used for performing either continuity or circuit tests. The same testing device may be utilized for performing either of the tests.

Elimination of the usual filament type indicating lamp heretofore generally utilized in testing devices is a very desirable improvement. The filament type of lamp is more expensive, is more fragile and hence subject to frequent breakage and, due to the relatively high current required to visibly light the lamp, is not adapted to conducting tests of equipment utilizing relatively small quantities of current. The discovery that false'or deceptive indications given by a neon type of lamp may be eliminated by coupling the capacitance or condenser in parallel with the neon type of lamp'renders commercially practicable and satisfactory a testing device embodying the neon type of lamp. Electricians, radio repair men and the like may use the present device in'conducting tests on electrical apparatus an'dcir'cuits without obtaining the highly objectionable and extremely false or deceptive indications heretofore existant in testing devices which attempted to utilize neon lamps to give visible indications;

I,The .present invention provides a small and compact testing device which may be carried in the pocket of a user and which may be used for conducting tests of either the continuity or the circuit type; the identical device is capable o-f performing either of these tests.

As various changes may be made in the form, construction and arrangement of the parts herein without departing from the spirit and scope of the invention and Without sacrificing any of its advantages, it is to be understood that all matter herein is to be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, I claim:

1. A testing device of the class described comprising the combination of a plurality of conductors each having a test prong connected with one end thereof and a contact terminal connected with another end thereof, a resistance unit in series With each of said conductors Iadjacent said test prongs, a gaseous tube electric discharge lamp rin series with one f said conductors and its resistance unit, a capacitance coupled in parallel with both said lamp and the resistance unit which is in series therewith, holder members securedrto said test prongs with one holder member carrying the resistance unit and lamp and condenser of one conductor and with another holder member carrying the resistance unit of another conductor, means attached with said conductors having yieldable members for releasably retaining said holder members, and -a contact bar carried by said means Iadapted to electrically connect together said contact terminals.

2. A testing device of the class described comprising the combination of a plurality of con- Tf ductors each having a test prong connected with one end thereof and a contact terminal of an attachment plug connected with another end thereof, a resistance unit in series with each of said conductors adjacent said test prongs, a gaseous tube electric discharge lamp in series with one of said conductors and its resistance unit;

a capacitance coupled in parallel with both said lamp and the resistance unit which is in series therewithfholder members secured tosaiditest prongs with one holder member enclosing the resistance unit and lamp and condenser of one conductor and with another holder membenenclosing the resistance unit of another conductor, means 4attached with said conductors 'having yieldable wall portions for releasably retaining said holder members, and a contact bar secured to said means adapted to electrically connect together said contact terminals of the attachment plug.

3. A testing device of the class described com-V prisingthe combination of a plurality of conductors each having a test prong connected with one end thereof and a contact terminal ofan attachment plug connected with another end thereof, a resistance unit in series with each of said conductors adjacent said test prongs, a gaseous tube electric discharge lamp in series with one of said conductors and its resistance unit, a capacitance coupled in parallel with both said lamp and the resistance unit which is in series therewith, holder members secured to said test prongs with one holder member enclosing the resistance unit and lamp and condenser of one conductor and with another holder member en-` closing the resistance unit of another conductor, means attached with said conductors `having spaced yieldable wall portions for releasably retaining said holder members and having a reduced portion for winding said conductors thereabout, and a contact bar secured `to said: meansV adapted to electrically connect together Asaid conf.

tact terminals of the attachment plug.

4. A device as claimed in claim 2 in which said contact bar is contained in a recess of the rst means and in which said yieldable Wall portions extend along opposite sides of 'said recess.`

- MORRIS PODELL.

REFERENCES CITED The following references are of record inthe file of this patent:

UNITED STATES PATENTS 

